1 /*
2  * Copyright (C) 2017 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package art;
18 
19 public class Test1906 {
20   public static final Object lock = new Object();
21 
22   public static volatile boolean SECOND_THREAD_RUN = true;
23   public static volatile boolean SECOND_THREAD_RUNNING = false;
24 
waitFor(long millis)25   public static void waitFor(long millis) {
26     try {
27       lock.wait(millis);
28     } catch (Exception e) {
29       System.out.println("Unexpected error: " + e);
30       e.printStackTrace();
31     }
32   }
33 
waitForSuspension(Thread target)34   public static void waitForSuspension(Thread target) {
35     while (!Suspension.isSuspended(target)) {
36       waitFor(100);
37     }
38   }
39 
run()40   public static void run() {
41     synchronized (lock) {
42       final Thread second_thread = new Thread(
43           () -> {
44             while (SECOND_THREAD_RUN) { SECOND_THREAD_RUNNING = true; }
45           },
46           "SECONDARY THREAD");
47       Thread self_thread = new Thread(
48           () -> {
49             try {
50               // Wait for second thread to start doing stuff.
51               while (!SECOND_THREAD_RUNNING) { }
52               Suspension.suspendList(Thread.currentThread(), second_thread);
53             } catch (Throwable t) {
54               System.out.println("Unexpected error occurred " + t);
55               t.printStackTrace();
56               Runtime.getRuntime().halt(2);
57             }
58           },
59           "TARGET THREAD");
60       try {
61         second_thread.start();
62         self_thread.start();
63 
64         waitForSuspension(self_thread);
65 
66         // Wait to see if second thread is running.
67         SECOND_THREAD_RUNNING = false;
68         waitFor(1000);
69 
70         if (SECOND_THREAD_RUNNING) {
71           System.out.println("Second thread running after first thread suspended self!");
72         } else {
73           System.out.println("Second thread suspended before first thread suspended self!");
74         }
75 
76         Suspension.resume(self_thread);
77         waitForSuspension(second_thread);
78         Suspension.resume(second_thread);
79         self_thread.join();
80         SECOND_THREAD_RUN = false;
81         second_thread.join();
82       } catch (Throwable t) {
83         System.out.println("something was thrown. Runtime might be in unrecoverable state: " + t);
84         t.printStackTrace();
85         Runtime.getRuntime().halt(2);
86       }
87     }
88   }
89 }
90